The present invention relates to an extra-high water pressure device and especially relates to an extra-high pressure water pump, which has an additional piston or lubricating oil piston, which is mechanically so simple and strong and provides necessary lubricating oil to a piston or main piston of the pump.
In general, a pump uses lubricating oil in the gap between the piston and the cylinder barrel in order to reduce friction thereinbetween. A low pressure water pump need not use lubricating oil because of low friction. However, lubricating oil is indispensable to the gap in case of an extra-high pressure water pump, since the friction at the gap thereinbetween is so high because the gap is so tight in order to prevent high pressured water in the cylinder barrel from leaking from the gap thereinbetween.
Extra-high pressure pushes water in the cylinder barrel of the pump into the gap. Consequently, lubricating oil in the gap is pushed out of the gap by the extra-high pressured water pushed into the gap, which causes the pump a high friction trouble.
A conventional extra-high pressure water pump has solved this high friction problem by utilizing a lubricating oil piston connected to the head of the main piston with an additional piston rod or lubricating oil piston rod. This is, the pump has a double piston comprising a main piston and a lubricating oil piston. The lubricating oil piston is connected to the main piston head with an additional piston rod. Therefore, the pump has an additional room or lubricating oil room between the lubricating oil piston and the main piston. Lubricating oil is pushed into the lubricating oil room by extra-high pressure as high as the water pressure in the pump. Hence, extra-high pressure of the lubricating oil in the lubricating oil room pushes back the extra-high pressured water, so that the main piston and the lubricating oil piston are prevented from the high friction problem.
A conventional extra-high pressure water pump, however, employs an external means to obtain extra high pressure to push lubricating oil into the lubricating oil room, which makes the pump complicated, bigger and expensive. And as a water hammer, a sudden pressure imbalance between water pressure and the lubricating oil pressure in the cylinder barrel breaks the lubricating oil piston, because the lubricating oil piston is firmly fixed to the additional rod projecting from the main piston head.
Of course, an ordinary extra-high water pump has not a serious water hammer problem since a worked material by water jet from a water jet gun is placed in a certain fixed distance from the water jet gun, which does not change a pressure load of the pump. Whereas, an extra-high pressure water pump with a handy carryable water jet gun has a serious water hammer problem, since the handy carryable water jet gun is moved to various worked materials during working. Consequently, distance between the handy carryable water jet gun and a worked material or load is always changed during working. Therefore, a sudden change of a worked material by moving of the gun gives a water hammer shock to the lubricating oil piston of the pump, which breaks the lubricating oil piston.
The less gap between a lubricating oil piston and a cylinder barrel that a pump has, the higher sealing the pump can obtain. However, the less gap between the lubricating oil piston and the cylinder barrel that the pump has, the higher friction therebetween the pump has. In order to solve the friction problem, a pump generally employs a piston ring. Since a piston ring for an extra-high pressure water pump is required higher sealing, the piston ring is required to seal gaps between the lubricating oil piston and the inner edge of the piston ring and between the cylinder barrel and the outer edge of the piston ring. Consequently, the pump has also a high friction problem between the gaps. Any prior art cannot solve this friction problem, whereas the present invention has solved this friction problem while keeping high sealing at the gaps by employing a double piston ring, which will be described in the detailed description of the invention herein.
A conventional extra-high pressure water pump employs a conventional check valve. Since the extra-high pressure water pump produces a high water pressure, the high water pressure is apt to pinch between a valve ball and a contact of the valve an impure monocular in water at the check valve. Since the pinched impure monocular between the valve ball and the valve contact keeps the check valve ajar, high pressured water from the pump leaks from the check valve. The present invention has also solved this leakage problem by employing a double check valve, which will be described in the detailed description of the invention herein.
The water-jet gun used with the extra-high water pump of the present invention is a small handy carryable gun as mentioned above. Therefore, this gun causes the above mentioned problem.
The extra-high pressure water pump used in the present invention has solved these problems.